FIG. 1 (Prior Art) is a diagram of system 1 involving a type of analog integrated circuit 2 and a microcontroller integrated circuit 3. Analog integrated circuit 2 is sometimes called a “Power Management Unit” or “PMU”. It is desired to be able to design and fabricate such a PMU for a custom application in a small amount of time. The custom application may, for example, require that PMU 2 include a number of different types of analog circuits. The analog circuits may, for example, be derived from integrated circuit Silicon Intellectual Property (SIP) blocks such as those commercially available from Faraday Technology Corporation of Hsinchu, Taiwan.
The analog circuits are designed and laid out so that they pack together and are of irregular shapes as illustrated in FIG. 1. Parts of the analog circuits may be shared. One example of such an analog circuit is a voltage regulator. The voltage regulator might be configurable to output a selectable voltage. The voltage regulator might be configurable so that a current limit of the regulator can be changed. The various analog circuits of PMU 2 might be configurable such that if PMU 2 is configured in one fashion, then certain of the analog circuits are coupled to certain of the integrated circuit input/output (I/O) terminals, whereas if PMU 2 is configured in another fashion then the analog circuits are coupled to others of the I/O terminals. Each of the analog circuits of PMU 2 may, for example, be configurable so that it can be enabled or disabled. There are many ways that the various analog circuits of an analog integrated circuit such as PMU 2 may be designed to be configurable.
However, each PMU is a custom design, which is functionally limited to the analog circuits that comprise the specific design. Due to the irregular shapes of the analog circuits and the sharing of some analog circuits, considerable engineering effort is required to significantly alter the functional capability of a particular PMU. For example, a first customer may require four channels each outputting a controlled voltage of a different magnitude and a first design may be made to fulfill the requirement. A second customer may require eight channels each outputting a controlled voltage of a different magnitude. To fulfill the additional requirements of the second customer, additional voltage regulators may be added to the design for the first customer. Using existing analog circuit design techniques and SIP blocks, a separate design and significant engineering effort must be directed to meet the second requirement. The physical layout must be updated, new routing layers designed, and a revised memory structure designed to address each new regulator.
For the same reasons, considerable engineering effort is required to substitute an analog circuit of one type for an analog circuit of another type to achieve a similar function. For example, to replace a buck converter with a linear voltage regulator, detailed integrated circuit layout, routing, and layout issues must be resolved by a design engineer to generate physical layout data suitable for integrated circuit fabrication.
These limitations result in increased engineering costs and time to market for custom PMU solutions. Although, PMUs may be designed with a large range of functionality that may be largely disabled to meet a particular set of customer requirements, this approach leads to PMUs that are both costly and large. The PMUs typically include substantial circuitry that is not utilized in the end product.